1. Field
The object of the invention is a method and an arrangement for opening and closing a suspended ceiling or corresponding of an elevator car and also a locking device.
Hereinafter the method, arrangement and locking device according to the invention are jointly referred to as the solution according to the invention.
2. Description of Conventional Art
The ceiling, i.e. the suspended ceiling, of an elevator car often comprises a plurality of luminaires for illuminating the elevator car. The lamps of these luminaires must be changed from time to time. Additionally, the space between the suspended ceiling and the roof often comprise various devices that need to be serviced periodically. For this reason access to the space between the suspended ceiling and the roof is in practice an absolute requirement. Access is often arranged from below, in which case the suspended ceiling of the car must be somehow lowered down to enable access.
In prior-art solutions a screw fixing, for example, is generally used, in which case the suspended ceiling of the elevator car is fixed into position by means of a number of screws. A problem in these solutions is that it is difficult for one person to open the suspended ceiling because the more he/she opens the screws, the more the ceiling tends to open at the same time and often warps downwards unevenly. It is difficult for one person to open the ceiling from one side of the ceiling and at the same time to prevent the ceiling from falling on the other side. This is a big problem particularly with large ceilings. It is also difficult for one person to fix the suspended ceiling back into position. Thus generally, for example, for this reason at least two persons are needed for changing a lamp. Another drawback is the slowness of opening and re-fixing the suspended ceiling because there are so many screws to be opened and fastened. One drawback is also that fastening of some fixing screws can easily be forgotten in the fixing phase, in which case the fixing of the suspended ceiling weakens and the suspended ceiling may, as a result of vibration and other stress, suddenly fall down on top of the passengers of the elevator.
Prior art also includes solutions, in which a suspended ceiling, is fixed into position e.g. by means of fixing elements to be turned around the vertical axis, which elements form a horizontal support surface. When it is desired to lower the suspended ceiling down, the fixing elements are turned around their vertical axis, e.g. approx. 90 degrees, in which case the fixing elements turn away from their support surface and the suspended ceiling can be lowered down. A problem in this solution also is that it is difficult for one person to open the suspended ceiling because the more he/she opens the fixing elements, the more the ceiling tends to open at the same time and often warps downwards unevenly. It is then difficult for one person to open the ceiling from one side of the ceiling and to prevent at the same time the ceiling from falling on the other side. It is also difficult for one person to fix the suspended ceiling back into position. One drawback also in this solution is that fixing of some fixing elements can easily be forgotten in the fixing phase, in which case the fixing of the suspended ceiling weakens and the suspended ceiling may, as a result of vibration and other stress, suddenly fall down on top of the passengers of the elevator. Another problem is that if the fixing elements are only supported by the surface below them, the fixing elements can produce noise when the elevator travels, which noise is caused by various vibrations of the elevator car.